Shapable antenna beams for cellular networks

ABSTRACT

Systems and methods are disclosed which provide aggressively sculpted or shaped antenna beams, such as sector antenna beams, for use in communication networks. Preferred embodiments use passive antenna feed networks, preferably configured as personality modules, which are adapted for corresponding topological and morphological features. Preferred embodiment feed networks may be coupled to linear or curvilinear antenna arrays to provide antenna beams having a desired contour. Using the disclosed systems and methods path loss variance is minimized for improved system capacity and/or signal quality. Moreover, the disclosed systems and methods provide for reduced average transmission power levels further allowing increased capacity and/or signal quality.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Divisional Application of and claimspriority to U.S. patent application Ser. No. 09/878,599, filed Jun. 11,2001 now U.S. Pat. No. 7,031,754 and published Dec. 19, 2002, entitled“Shapable Antenna Beams For Cellular Networks.” The present applicationis related to U.S. patent application Ser. No. 09/384,306 entitled“Antenna Deployment Sector Cell Shaping System and Method,” filed Aug.26, 1999, now abandoned, which is a continuation-in-part of U.S. Pat.No. 6,246,674 entitled “Antenna Deployment Sector Cell Shaping Systemand Method,” issued Jun. 12, 2001, which itself is acontinuation-in-part of U.S. Pat. No. 5,889,494 entitled “AntennaDeployment Sector Cell Shaping System and Method,” issued Mar. 30, 1999;also, Ser. No. 09/798,151 entitled “Dual Mode Switched Beam Antenna,”now abandoned, which is a continuation of U.S. Pat. No. 6,198,434entitled “Dual Mode Switched Beam Antenna,” issued Mar. 6, 2001; andU.S. Pat. No. 6,323,823 entitled “Base Station Clustered AdaptiveAntenna Array,” issued Nov. 27, 2001.; the disclosures of all of whichare hereby incorporated herein by reference.

TECHNICAL FIELD

The invention relates generally to wireless communications and, moreparticularly, to providing aggressive beam sculpting or shaping, such asfor sector beams of a cellular base station, to thereby provide cellboundary equalization.

BACKGROUND OF THE INVENTION

As wireless communications become more widely used, the number ofindividual users and communications multiply and, thus, communicationsystem capacity and communication quality become substantial issues. Forexample, an increase in cellular communication (e.g., cellulartelephony, personal communication services (PCS), and the like)utilization results in increased interference experienced with respectto a user's signal of interest due to the signal energy of the differentusers on the cellular system. Such interference is inevitable because ofthe large number of users and the finite number of cellularcommunications cells (cells) and frequency bands, time slots, and/orcodes (channels) available.

In code division multiple access (CDMA) networks, for example, a numberof communication signals are allowed to operate over the same frequencyband simultaneously. Each communication unit is assigned a distinct,pseudo-random, chip code which identifies signals associated with thecommunication unit. The communication units use this chip code topseudo-randomly spread their transmitted signal over the allottedfrequency band. Accordingly, signals may be communicated from each suchunit over the same frequency band and a receiver may despread a desiredsignal associated with a particular communication unit. However,despreading of the desired communication unit's signal results in thereceiver not only receiving the energy of this desired signal, but alsoa portion of the energies of other communication units operating overthe same frequency band. Accordingly, as the number of users utilizing aCDMA network increases, interference levels experienced by such usersincrease.

Accordingly, the quality of service (QOS) of communications and thecapacity of the communication network are typically substantiallyimpacted by interference or noise energy. For example, CDMA systems areinterference limited in that the number of communication units using thesame frequency band, while maintaining an acceptable signal quality, isdetermined by the total energy level within the frequency band at thereceiver. Accordingly, outage areas (locations where service is notsupported) of cellular networks are often defined in terms of a noise orinterference related threshold, such as establishing that the pilotE_(c)/N_(o) (energy per chip of the pilot to the total received spectraldensity) must be less than a predetermined threshold (e.g., −15 dB).

Cellular communications systems have typically been conceptualized foranalysis and planning purposes as a grid of hexagonal areas (cells) ofsubstantially equal size disposed in a service area. A base transceiverstation (BTS) having particular channels assigned thereto conceptuallymay be disposed in the center of a cell to provide uniform wirelesscommunications throughout the area of the cell. Therefore, a grid ofsuch cells disposed edge to edge in “honeycomb” fashion may be utilizedfor information with respect to the relative positions of a plurality ofBTSs for providing wireless communications throughout a service area.

However, it should be appreciated that the communication coverageassociated with a BTS typically varies substantially from thetheoretical boundaries of the cell due to cell topology and morphology.For example, topological characteristics (mountains, valleys, etc.)and/or morphological characteristics (large buildings, differentbuilding heights, shopping centers, etc.) result in different pathlosses experienced in different azimuthal directions from the BTS.Accordingly, in practice homogeneous signal quality is not providedthroughout the area of a cell.

Typically cells have been implemented as omni-trunks, where each cell isable to use each channel in the full 360° azimuth of a BTS, or sectoredconfigurations, such as breaking the cells down into 120° sectors suchthat each cell channel communicates in the 120° azimuth an associatedsector. However, because of the irregular boundaries experienced inactual cell implementations (e.g., path loss variance), a user movingabout a cell and even a sector may experience a wide variety ofcommunication conditions, including outage conditions (e.g., E_(c)/N_(o)□−15 dB) or poor quality of service. For example, this user may moveonly a few degrees in azimuth with respect to a BTS and experiencesignificant signal quality degradation. Accordingly, this user mayexperience unacceptable communication conditions, such as theaforementioned outage conditions, when noise or interference levels areotherwise generally within acceptable limits for operation within thenetwork.

Both the user's signal of interest, such as a serving pilot signal, andinterference associated therewith are typically subject to log-normalshadowing. Accordingly, the communication conditions experienced aredependent on the variance of both.

It can therefore be appreciated that the capacity of the cell may beunnecessarily limited and/or the quality of communications providedthereby may be substandard if the quality of various signals of interestwith respect to individual users is not maintained and/or interferenceenergy is not controlled. A need therefore exists in the art for systemsand methods which are adapted to provide a substantially uniformcommunication condition throughout an area, such as a cell or a sectorof a cell.

SUMMARY OF THE INVENTION

The present invention is directed to a system and method whichsubstantially equalizes communication system service area boundaries tothereby provide a substantially uniform communication conditionthroughout such service areas. Implementing aggressive cell sculptingaccording to the present invention, preferred embodiments change a cellfootprint to provide a desired cell boundary in response to celltopology and/or morphology features. Preferably, aggressive cellsculpting according to the present invention remediates radial varianceof signal communication within a cell, e.g., variance of communicationconditions throughout various degrees of azimuth, to thereby provideincreased communication capacity and/or improved quality of service.Moreover, implementation of preferred embodiments of the presentinvention includes careful cell planning to provide load balancing toincrease communication capacity and/or improve quality of service.

A preferred embodiment of the invention utilizes antenna arrays having arelatively large number of antenna elements to provide aggressive beamsculpting. Such arrays are preferably coupled to a feed networkproviding desired signal manipulation, e.g., complex weighting ofsignals providing amplitude and/or phase relationships of signalsassociated with the antenna elements of the array, providing such beamsculpting.

Preferred embodiments of the present invention implement passivenetworks for providing aggressive beam sculpting, such as for sectorbeams of a cellular base station, to thereby provide cell boundaryequalization. Feed networks utilized according to the present inventionpreferably comprise microstrip line and/or air-line busses, or otherpassive feed circuitry, which may be relied upon to conduct signals andprovided desired manipulation of attributes thereof. For example,air-line transmission lines may be adapted to provide desired signalpower splitting, such as through providing junctions having desiredimpedance relationships, and/or delays, such as through providing linelengths associated with desired amounts of propagation delay.

The preferred embodiment feed networks provide a “personality module”which may be disposed at the masthead or tower-top with theaforementioned antenna array to provide operation as described herein.Accordingly, operation as described herein may be provided withoutdeploying expensive signal processing equipment and/or signal processingequipment sensitive to operation in such environments at the masthead.Moreover, preferred embodiments, implementing such a personality module,may be deployed without requiring change to a cell site shelter andwithout substantially affecting system reliability.

The present invention may be used with any air interface used incellular and personal communication services (PCS) networks, such as airinterfaces defined by the AMPS, IS-54, IS-136, IS-95, and GSM standards,to provide improved operation as described herein. Additionally, antennaarrays of the present invention may be used in conjunction with signaldiversity techniques, such as transmit diversity, if desired.

The foregoing has outlined rather broadly the features and technicaladvantages of the present invention in order that the detaileddescription of the invention that follows may be better understood.Additional features and advantages of the invention will be describedhereinafter which form the subject of the claims of the invention. Itshould be appreciated by those skilled in the art that the conceptionand specific embodiment disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present invention. It should also be realized by thoseskilled in the art that such equivalent constructions do not depart fromthe spirit and scope of the invention as set forth in the appendedclaims. The novel features which are believed to be characteristic ofthe invention, both as to its organization and method of operation,together with further objects and advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. It is to be expressly understood, however, thateach of the figures is provided for the purpose of illustration anddescription only and is not intended as a definition of the limits ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, reference isnow made to the following descriptions taken in conjunction with theaccompanying drawing, in which:

FIG. 1 shows coverage associated with a typical prior art cellularnetwork as resulted from topological and morphological features;

FIG. 2 shows the result of cell sculpting in response to equalizationaccording to the present invention;

FIGS. 3A-G show various examples of beam shaping achievable according tothe present invention;

FIG. 4 shows a schematic diagram of an exemplary antenna array beamforming network as may be provided as a personality module according tothe present invention;

FIG. 5 shows a preferred embodiment implementation of a portion of apassive personality module of the present invention;

FIGS. 6A and 6B shows alternative configurations for portions of apassive personality module of the present invention;

FIG. 7 shows simulated results of outage verses loading for various footprint radius variances;

FIG. 8 shows simulated results of traffic channel power verses loadingfor various foot print variance values of the present invention;

FIG. 9 shows simulated results of outage verses active subscribers forvarious foot print variance values of the present invention;

FIG. 10 shows a histogram of site sector loading changes as experiencedin a particular market area;

FIG. 11 shows the probability of loading changes as derived from thehistogram of FIG. 10;

FIG. 12 shows a preferred embodiment curvilinear antenna arrayconfiguration according to the present invention; and

FIG. 13 shows a preferred embodiment schematic diagram of circuitrycoupling the antenna array configuration of FIG. 12 to base transceiverstation equipment.

DETAILED DESCRIPTION OF THE INVENTION

As illustrated in FIG. 1, cellular communications systems have typicallybeen conceptualized for analysis and planning purposes as a grid ofhexagonal areas (cells) of substantially equal size disposed in aservice area. For example, cells 101, 102 and 103 of FIG. 1 areidentified with the areas of communication associated with basetransceiver stations (BTSs) 110, 120, and 130, respectively.Accordingly, service area 100 is provided communication servicesthroughout by “honeycombed” deployment of such cells.

However, the communication coverage associated with a BTS may varysubstantially from the theoretical boundaries of the hexagonal cell dueto cell topology and morphology. For example, as shown in FIG. 1 cell101 includes morphological features disposed therein. Accordingly,sector 112, having building 140 disposed therein, presents a contourappreciably different than the cell boundary the sector theoreticallyfollows due to signal fading and/or shadowing associated therewith.Likewise, sector 111, having buildings 141 and 142 disposed therein,presents a contour appreciably different than the cell boundary thatsector theoretically follows also due to signal fading and/or shadowingassociated therewith. Similarly, cells 102 and 103 include topologicalfeatures disposed therein. Accordingly, sector 121, having mountain 150disposed therein, presents a contour appreciably different than the cellboundary due to a significant shadow cast by the mountain. Sector 131,having lake 160 disposed therein, presents a contour appreciablydifferent than the cell boundary due to omission of attenuatingstructure associated with the lake.

Although no topological or morphological features are illustrated withinsector 113 of cell 101, the contour of sector 113 is illustrated toblossom beyond the boundary of the cell boundary. It is often attemptedto address such an area of overlap, to varying degrees of success,through the use of down-tilt at the sector antenna. Such down-tilt isgenerally applied to all sectors of a typical prior art cellular systemin an attempt to minimize areas of overlap between the cells.

It should be appreciated that the topological and morphological featuresillustrated in FIG. 1 are simplified in order to aid in understandingthe present invention. Accordingly, an actual cellular deployment mayinclude topological and morphological features substantially morecomplex than those illustrated, such as including many more features ina cell and/or a sector as well as mixing both morphological andtopological features. Moreover, it should be appreciated that all suchfeatures which affect the propagation of communicated signals are notrepresented. For example, features such as trees, valleys, highways, andthe like may significantly impact the contour of a cell. Additionally,such features may change over time, such as seasonally as with deciduoustrees.

It can readily be seen from FIG. 1 that there are outage areas(locations where service is not supported) within the cells. Forexample, due to the effects of signal shadowing, sector 121 does notfully cover a corresponding portion of cell 102. Moreover, areas ofoutage are typically defined with reference to noise energy and,therefore, are more extensive than initially apparent from FIG. 1. Forexample, in some cellular systems in common use today outage areas aredetermined as any area in which a particular pilot E_(c)/N_(o) (energyper chip of the pilot to the total received spectral density) is lessthan a predetermined threshold, such as −15 dB. Accordingly, areashaving high noise characteristics, such as the areas where sectors 112and 121 overlap and where sectors 112 and 131 overlap, in addition toareas where a particular signal of interest receive strength isrelatively low, may experience outage conditions. Moreover, both theuser's signal of interest, such as a serving pilot signal, andinterference associated therewith are typically subject to log-normalshadowing. Accordingly, the communication conditions experienced aredependent on the variance of both.

Because of the irregular boundaries experienced in actual cellimplementations (e.g., path loss variance), a user moving about a celland even a sector may experience a wide variety of communicationconditions, including the aforementioned outage conditions, or poorquality of service. In CDMA networks, in particular, performance isdirectly related to interference control and, therefore, such path lossvariances may significantly impact performance. GSM protocols have beenmigrating into the spread spectrum arena by adopting frequency hopping,bringing GSM systems closer to CDMA system characteristics (frequencyreuse factor of 1). Accordingly, GSM networks are prone to appreciableperformance degradation associated with path loss variance. For example,the user may move only a few degrees in azimuth with respect to a BTSand experience significant signal quality degradation.

However, the outage areas and areas in which poor signal quality isexperienced are typically to be minimized in a communication network.For example, typical network designs strive to provide networks in whichoutage areas are not more than 2% of the network service area.Accordingly, such network designs often include the use of antennadown-tilt (i.e., directing the broadside of an antenna array a fewdegrees toward the ground) in an attempt to minimize areas of overlapbetween adjoining cells. However, such prior art techniques provide onlylimited success as they are not fully responsive to cell topology andmorphology features.

Accordingly, preferred embodiments of the present invention implementaggressive cell sculpting to change a cell footprint and provide adesired cell boundary in response to cell topology and/or morphologyfeatures and may be used with a variety of air interfaces, such as airinterfaces defined by the AMPS, IS-54, IS-136, IS-95, and GSM standards.Preferably, cell sculpting according to the present invention providesair link signals adapted with respect to the particular path lossdifferentials experienced and, therefore, provides a reduction of theaverage signal energy within a cell. Such reduction of average transmitpower required to support air links or connections will directlycontribute to capacity increase, in addition to minimizing pilotpollution and the soft handoff rate allowing for greater networkrobustness and reduced resource usage.

Directing attention to FIG. 2, the cells of FIG. 1 are shown havingbenefit of the present invention to provide cell boundaries moreconsistent with that of the theoretical hexagonal cells. Preferably,cell sculpting according to the present invention remediates the radialvariance of signal communication shown in FIG. 1. Accordingly, the cellsculpturing of FIG. 2 provides contours of illustrated sectors 211, 212,213, 221, and 231 substantially consistent with the corresponding cellboundaries, despite the topological and/or morphological featuresdisposed therein. For example, where the path loss angular profile isknown (e.g., derived from a cell footprint), an antenna pattern can beformed such that path loss and antenna gain summed (as a function ofazimuth) provide a substantially consistent result throughout theazimuth of an antenna beam sculpted according to the present invention.Stated another way, Path Loss+Antenna Gain (as function of azimuth)Variance is minimized.

Path loss angular profile information useful in providing cell sculptingaccording to the present invention may be acquired in a variety of ways.For example, drive test information may gathered to empiricallydetermine angular profile information, or some portion thereof.Additionally or alternatively, direction finding information andcommunication link attributes, such as receive signal strength, carrierto noise ratio, and the like, may be utilized in determining angularprofile information. For example, GSM reverse link characteristics(hopping sequence, training sequence, etc.) are well known to theoperator and, therefore, traffic loading as a function of azimuth may bedetermined using a simple radio direction finding system therewith. Thisinformation may be used according to the present invention to determinecell site beam shaping.

For example, energy radiated from a sector antenna array of BTS 110 mayprovide sufficient energy in the azimuthal direction corresponding tobuilding 140 to remediate a shadowing affect associated therewith.Likewise, energy radiated from a sector antenna array according to thepresent invention may provide energy directed such that multi-path andshadowing effects associated with buildings 141 and 142 are remediated.A sector antenna array of the present invention may further provideenergy radiation adapted to remediate the shadowing effects of mountain150, including providing increased antenna gain in correspondingdirections of the azimuth, and propagation effects of lake 160, such asproviding decreased antenna gain in corresponding directions of theazimuth.

It should be appreciated that, although described above with referenceto signals radiated from the BTSs (i.e., the forward link), cellsculpting of the present invention may be utilized in any linkdirection, whether forward or reverse links, and with communicationsystems other than the preferred embodiment BTSs. Moreover, althoughdiscussed with reference to sector antenna arrays, the present inventionis not limited to use with sector antenna arrays or even with sectorizedsystems. Similarly, operation of the present invention is not limited touse of either the 120° sectors or sectors of equal size shown in theillustrated embodiment. For example, cell sculpting according to thepresent invention may provide cells and/or sectors of unequal sizeand/or shape, or otherwise specifically adapted, to provide loadbalancing to increase communication capacity and/or improve quality ofservice.

In providing cell sculpting according to the present invention, desiredcell contours are preferably provided using aggressive antenna beamshaping techniques. Accordingly, the use of antenna down-tilt to definea cell's boundaries may be limited or avoided. For example, a particularcell's boundary configuration, topological features, and/ormorphological features may provide a situation in which particularportions of the azimuth should be substantially restricted in outboardreach (e.g., in prior art systems a substantial amount of antennadown-tilt applied to avoid cell boundary overlap) whereas other portionsof the azimuth should be substantially extended in outboard reach (e.g.,in prior art systems a minimal amount of antenna down-tilt applied tofully cover a portion of the cell). According to the present invention,the contour of the cell is sculpted in response to the situationexperienced and, therefore, the degrees of azimuth may be substantiallyindividually addressed, unlike prior art applications of down-tilt whichaffect a sector substantially equally throughout its azimuth. Forexample, sector 221 of FIG. 2 may be provided with no down-tilt in orderto better eliminate the shadowing effects of mountain 150 while stillmaintaining a proper contour with respect to portions of the sector notsubstantially affected by mountain 150.

Accordingly, it should be appreciated that cell footprints can be“smoothed” according to the present invention to become as close aspossible to the theoretical hexagon, or other desired shape, as shown inFIG. 2. This “spatial equalization” can provide for such advantages asoutage reduction, allowing for higher loading and increased networkcapacity, reduced signal “penetration” from one cell to another, therebyreducing pilot pollution, reducing the expected number of pilots thatexceed the “TADD” threshold, thereby reducing soft handoff rate, andreduced probability of low E_(c)/N_(o) regions within the cell, therebyincreasing the cell capacity.

The sculpturing capability, or the resolution of the azimuthalcontouring, is typically related to a number of elements in the array.To significantly change the cell footprint, antenna arrays utilizedaccording to the present invention should have sufficient numbers ofantenna elements (in the preferred embodiment, columns) allowingaggressive beam synthesis. Therefore, the present invention preferablyutilizes antenna arrays having a relatively large number of antennaelements, whether disposed in a linear or curvilinear configuration, toprovide aggressive beam sculpting, such as may be utilized to addresstopological and morphological features to result in desired cellcontours such as illustrated in FIG. 2. For example, antenna arraysprovided in panel or conic configurations such as shown and described inthe above referenced patent application entitled “Dual Mode SwitchedBeam Antenna” and in commonly owned U.S. Pat. No. 6,188,272 entitled“System and Method for Per Beam Elevation Scanning,” the disclosure ofwhich is hereby incorporated herein by reference, may be utilizedaccording to the present invention. The use of curvilinear arrays may beadvantageous in particular situations due to the ability to typicallygenerate wider beams (e.g., 200° beam widths) with such arrays.

Directing attention to FIGS. 3A-3G, examples of beam sculpting toprovide attributes responsive to hypothetical topological and/ormorphological features are shown. In each of FIGS. 3A-3G, the uppercurve (311-317 respectively) represents the desired radiation patternattributes, responsive to the aforementioned topological and/ormorphological features, and the lower curve (301-307 respectively)represents the simulated results using a particular antenna arrayaccording to the present invention. FIGS. 3A-3D provide examples ofcurvilinear array beam sculpturing and FIGS. 3E-3G provide examples oflinear array beam sculpturing. Specifically, FIGS. 3A-3D providesimulation results for beam sculpturing according to the presentinvention using a semi-circular array having 17 antenna columns spacedequidistant with respect to one another. FIGS. 3E-3G provide simulationresults for beam sculpturing according to the present invention using aflat panel array having 8 columns spaced equidistant with respect to oneanother.

Antenna arrays utilized according to the present invention arepreferably coupled to a feed network providing desired signalmanipulation, e.g., complex weighting of signals providing amplitudeand/or phase relationships of signals associated with the antennaelements of the array, to provide the above described beam sculpting. Itshould be appreciated that typical prior art beam shaping solutions,such as those using adaptive beam forming responsive to a mobile unit'sposition, utilize a beam-forming device requiring a significant amountof hardware (LPAs, controllable phase shifters, etc.), some or all ofwhich are not well suited for deployment at a masthead or tower-top withan antenna array, which adds to the expense and/or complexity of suchsystems. Preferred embodiments of the present invention implementpassive networks for providing aggressive beam sculpting therebyallowing low cost use of many elements, allowing aggressive sculpting,to thereby provide cell boundary equalization. Such embodiments may bedeployed at the masthead as part of the antenna array assembly. Thisarrangement relieves the need for a large amount of hardware asmentioned above and, hence, allows for larger number of antenna elementsin the array as required for aggressive sculpturing.

Preferred embodiment feed networks utilized according to the presentinvention comprise microstrip line and/or air-line busses which may berelied upon to conduct signals and provided desired manipulation ofattributes thereof. For example, air-line transmission lines may beadapted to provide desired signal power splitting, such as throughproviding junctions having desired impedance relationships, and/ordelays, such as through providing line lengths associated with desiredamounts of propagation delay. Preferred embodiment feed networks providea “personality module” which may be disposed at the masthead with theantenna array to provide operation as described herein.

The concepts applicable to providing a preferred embodiment passivepersonality module are provided below with respect to implementationusing a beam shaping network based on micro strip lines design. However,it should be appreciated that the personality module described is forillustrative purposes only and is not intended to limit the presentinvention to the configuration described.

In providing preferred embodiment personality modules according to thepresent invention, the system designer is presented with a need todistribute seemingly arbitrary power and phase to specific loads. Forthe purposes of the illustrative embodiment, it will be assumed thatthese loads can represent the drive point impedance of a column ofdipole antennas or at the column these loads can represent theindividual dipoles themselves. Additionally, it will be assumed that atypical 50 Ω coaxial line is used to deliver radio frequency (RF) energyfrom some generator to an air-line transmission line, wherein anair-line is substantially identical to a microstrip transmission linewith the special condition that the dielectric between the microstripand the ground plane is in fact air.

A very simple example of a power and phase distribution network for usewith 16 loads is shown in FIG. 4. Specifically, FIG. 4 shows columns401-408, including loads 411 and 412, 421 and 422, 431 and 432, 441 and442, 451 and 452, 461 and 462, 471 and 472, and 481 and 482respectively, coupled to generator 490. Columns 401-408 may correspondto antenna element columns of 2 antenna elements each (loads 411, 412,421, 422, 431, 432, 441, 442, 451, 452, 461, 462, 471, 472, 481, and482) forming a linear or curvilinear array for communicating an RFsignal associated with a transceiver (generator 490). It should beappreciated that the distribution network shown in FIG. 4 illustrates asymmetric load which, depending upon topological and/or morphologicalfeatures of the service area actually served, may not be the case.However, it is believed that a discussion of providing a passive feednetwork according to the present invention to a simple symmetric loadwill more readily allow an understanding of the concepts presented andfacilitate their application to feed networks providing aggressive beamsculpting according to the present invention.

In the exemplary scenario, it is assumed that the cell topology andmorphology suggest that, according to the present invention, one Wattper load, all at the same phase, should be delivered in this system toprovide a desired cell contour. Because the load is symmetrical, a firstside of the feed assemblage (feed network portion 400) will be discussedherein, with the understanding that the same design considerations applyto the second side of the feed assemblage.

Directing attention to FIG. 5, feed network portion 400 is shown in apreferred embodiment microstrip pattern, where center junction 590preferably couples to generator 490 and transmission line ends 551, 552,561, 562, 571, 572, 581, and 582 preferably couple to loads 451, 452,461, 462, 471, 472, 481, and 482 respectively. It should be appreciatedthat relative widths of the microstrip pattern are approximated in theillustration in order to show the preferred embodiment impedance ratiosutilized in passively distributing power for antenna beam shaping.

In the example, it is desired to provide equal power (1 Watt) to allloads, accordingly center junction 590 provides 2 microstrip lines ofequal size (equal impedance) to thereby provide a power splitter equallydividing power between the first feed network portion and the secondfeed network portion. For example, where generator 490 provides an RFsignal of 2P Watts (in the example 2P=16) to center junction 590, anapproximately 1P Watt (in the example P=8) RF signal will be provided tofeed network portion 400.

Power splitting is also provided at each of junctions 505, 506, 507, and508 to thereby provide a desired amount of power (in the example 1 Watt)to corresponding ones of the loads. For example, at junction 505microstrips having particular relative sizes are illustrated in FIG. 5extending up, down, and to the right. The up and down portions ofjunction 505 lead to ends 551 and 552 respectively, where it is desiredto deliver ⅛ of the power available at this junction to the loadscoupled thereto. Accordingly, the impedance associated with the upportion of junction 505 (Zu) is 8 times the impedance of the supplyingmicrostrip (Zo). Similarly, the impedance associated with the downportion of junction 505 (Zd) is 8 times the impedance of the supplyingmicrostrip (Zo). It should be noted that the ratio of line impedance isthe reciprocal of the desired power distribution, e.g., ⅛ P is relatedto 8Zo. As ¼ of the power of the signal input at junction 505 has beendistributed in the up (⅛ P) and down (⅛ P) portions thereof, ¾ of thepower remains for transmission to junction 506. Accordingly, theimpedance ratio of the right portion of junction 505 is 4/3 Zo.

At junction 506 microstrips having particular relative sizes are againillustrated. Defining P′ to be ¾ P and Zo′ to be the impedance of themicrostrip coupling junctions 505 and 506, an impedance relationship asdescribed above with respect to junction 505 can be appreciated.Specifically, in the illustrated example, P′ (¾ P), or 6 Watts, isprovided to junction 506 for supplying ⅙ P′ (⅛ P), or 1 Watt, to ends561 and 562 corresponding to up and down portions of junction 506 and,accordingly, the up and down portions of junction 506 are provided animpedance of 6Zo′. Correspondingly, the impedance associated with theright portion of junction 506 is 3/2 Zo′, corresponding to thetransmission of ⅔ P′ (½ P).

It should be appreciated that the right portion of the microstripleaving junction 506 is relatively thin due to the reductions in sizeassociated with power splitting at junctions 505 and 506. Accordingly,it may be desirable to increase the size of the microstrip, such as toavoid its behaving as a fuse link, in coupling junctions 506 and 507.The illustrated embodiment includes quarter wave transitions 501 and 502to increase the microstrip line thickness. The use of quarter wavetransitions 501 and 502 do not alter the power distribution at junction506 due to their disposition at the quarter wave position in thetransmission line. It should be appreciated that, in addition toproviding a microstrip coupling junctions 506 and 507 which has beensubstantially increased in size, the use of the preferred embodimentquarter wave transitions provide an input impedance at junction 507 moreamenable to the impedance ratios of the preferred embodiment.

At junction 507, P″ is defined to be ⅔ P′ (½ P) and Zo″ is defined to bethe impedance of the microstrip coupling junctions 506 and 507.Accordingly, in the illustrated example, P″ (½ P), or 4 Watts, isprovided to junction 507 for supplying ¼ P″ (⅛ P), or 1 Watt, to ends571 and 572 corresponding to up and down portions of junction 507 and,accordingly, the up and down portions of junction 507 are provided animpedance of 4Zo″. Correspondingly, the impedance associated with theright portion of junction 507 is 2 Zo″, corresponding to thetransmission of ½ P″ (¼ P).

The right portion of the microstrip leaving junction 507 is againrelatively thin due to the reduction in size associated with powersplitting. Accordingly, the illustrated embodiment includes quarter wavetransitions 503 and 504 to increase the microstrip line thicknessconnecting junctions 507 and 508.

At junction 508, P″ is defined to be ½ P″ (¼ P) and Zo″ is defined to bethe impedance of the microstrip coupling junctions 507 and 508.Accordingly, in the illustrated example, P″ (¼ P), or 2 Watts, isprovided to junction 508 for supplying ½ P″ (⅛ P), or 1 Watt, to ends581 and 582 corresponding to up and down portions of junction 508 and,accordingly, the up and down portions of junction 508 are provided animpedance of 2 Zo″. As all power provided to junction 508 is to beprovided to loads corresponding to the up and down portions, there is noright portion of junction as is provided in junctions 505, 506, and 507.

Although the illustrative embodiment provides equal power distribution,it will be readily appreciated that changes in the impedance ratioscorresponding to the desired changes in power distribution may beutilized in providing antenna beams having a different shape than theembodiment represented in the illustration. Likewise, although in phasesignals are provided to the loads in the illustrated embodiment, it willbe readily appreciated that microstrip line lengths may be altered(e.g., lengthened with respect to one load to provide a phase delayrelative to another load) to provide a desired phase progressionutilized in providing antenna beams having a different shape than theembodiment represented in the illustration.

The above example has been discussed with respect to changing microstripline widths in order to provide the desired impedance ratios. However,it should be appreciated that microstrip line impedance is not only afunction of line width, but also of substrate thickness, dielectricconstant and thickness of the conductor. Accordingly, any or all of suchmicrostrip line attributes may be altered in providing impedance ratiosaccording to the present invention. For example, different dielectricmaterials may be introduced at various portions of the junctions inorder to provide a desired impedance ratio, if desired.

It should be appreciated that, in providing a feed network according tothe preferred embodiment, microstrip line lengths may be desired whichare physically longer than a distance to be traversed by the line. Forexample, in feeding antenna elements or columns of a curvilinear array,the antenna element or antenna column feed point along the curvilinearground could be less than a quarter wavelength. Similarly, in providinga desired amount of phase shift, a transmission line may be desiredwhich is longer than the distance between antenna elements or antennacolumns. Accordingly, various microstrip configurations may be utilizedaccording to the present invention to provide desired transmissioncharacteristics.

Directing attention to FIGS. 6A and 6B, the use of “zigzag” microstripconfigurations to provide desired transmission line lengths is shown.Specifically, junctions 601, and 611-614 are shown disposed along amicrostrip transmission line. Junction 601 may, for example, be aconnection point for a signal generator or receiver. Junctions 611-614may, for example, provide connection to antenna elements or antennacolumns of a panel or curvilinear array. Because the locations ofjunctions 611-614 in the illustrated embodiment are determined by thephysical attributes of the antenna, it may be desired to provide atransmission line longer than spacing there between. Accordingly, themicrostrips of FIG. 6A are provided with bends to provide extendedtransmission line lengths between the junction coupling points. Forexample, the microstrip lines coupling junction 601 with junctions 612and 613 may be provided in a length which is a function of thetransmitted signal half wavelength whereas the microstrip lines couplingjunctions 611 and 612 and junctions 613 and 614 may be provided in alength which is a function of the transmitted signal full wavelength.

Using such a technique, the microstrip lines may be formed with anydesired length to thereby provide desired phase relationships. Forexample, referring to FIG. 6B, the microstrip coupling junctions 613 and614 may be extended to provide a phase delay in the signal provided tojunction 614, if desired.

A cellular network using aggressive cell sculpting, such as may beprovided using the preferred embodiment passive feed networks discussedabove, was simulated to determine the effect of implementation of thepresent invention with respect to network conditions which mighttypically be expected. Specifically, a two-tier, 19 cell network wascomputer modeled assuming an exponential path loss exponent of 4, whichis a typical value for a very dense urban environment. In deriving thesimulation results, a very large number of locations were randomlychosen inside the center cell of the aforementioned 19 cell network, andsignals to each such location from all the base stations were shadowed.The standard deviation of the log-normal shadowing (path loss variance)was varied in the simulation between 0 to 10 dB, where shadowing hasbeen found to vary between 8 to 10 dB in such networks not implementingthe present invention. Specifically, the shadowing in the simulation wasvaried as a function of angle because of the preferred embodiment'sapproach of equalizing the gains as a function of the azimuthal angle.Accordingly, the simulation results are discussed herein with respect torelative gain associated with such angular equalization.

It should be appreciated that one of the most important quality ofservice (QOS) measurements is the percentage of cell area with propercoverage. The area of such coverage within a cell may be quantified bymeasuring communication characteristics, such as the receive parameterE_(c)/I₀ (ratio of the energy per chip of the pilot channel to the totalreceived spectral density), at locations within the cell. For example,in IS-95 CDMA communication systems the E_(c)/I₀ parameter as measuredat a receiver should be greater than −15 dB if adequate communicationlinks are to be provided. Accordingly, in many systems if E_(c)/I₀<−15dB, receiving systems, such a mobile subscriber units, are unable todemodulate a signal and, therefore, a coverage hole or outage is presentat that location.

The above mentioned receive parameter E_(c)/I₀ may be determined asfollows:

(1)

-   -   where,    -   =Fraction of the total power on the pilot channel;    -   =Gain of the BTS antenna;    -   =Distance related path loss;    -   =log-normal shadowing random variable;    -   =Standard deviation of the shadowing (in dB); and    -   =Total received power.

The above mentioned total power I₀ may be determined as follows:

-   -   where,    -   =loading of cell i; and    -   =Thermal noise.

In deriving the simulation results, the E_(c)/I₀ for all the basetransceiver stations (BTS) associated with the aforementioned 19 cellswere measured at each of the randomly selected locations. The BTS withthe highest E_(c)/I₀ was assumed to be the BTS providing communicationto that location. Additionally, each BTS was assumed to be equallyloaded, i.e., the percentage of the maximum permissible power beingtransmitted by the BTSs was assumed to be the same for all 19 BTSs.Loading may be thought of in the following relationship:Loading=Overhead+(Number of subscribers*average power of eachsubscriber).

FIG. 7 shows a graph of the simulation results presented as percentageof the cell area experiencing outage conditions (E_(c)/I₀<−15 dB) versespercent loading of the cells. The different lines of FIG. 7 present thesimulation results for particular values of the shadowing standarddeviation simulated. Specifically, lines 701-710 present the results for1-10 dB of shadowing standard deviation, respectively.

In a system where 2% outage is acceptable and wherein 9 dB of standarddeviation of the shadowing is experienced (as is often encountered insystems not implementing the present invention), it can be seen fromline 709 that the maximum loading for the system is 78%. However, if byusing cell sculpting according to the present invention the standarddeviation of the shadowing is reduced to 4 dB, then it can be seen fromline 704 that the maximum loading for the system is increased toapproximately 93%. Accordingly, the capacity gain for implementation ofthe present invention in such a system is (93-78)/78=20% or 0.8 dB.

It should be appreciated that the present invention provides additionalgain due to the decrease in the average required traffic channel powerassociated with the decrease in the standard deviation of the shadowing.The transmit power trends are shown in FIG. 8, wherein a graph of theaverage forward link traffic channel power as a percentage of the totalavailable power versus percent loading of the cells is provided forparticular values of the shadowing standard deviation. Specifically,lines 801-810 (it being appreciated that lines 801 and 802 substantiallyoverlap) present the transmit power trends for 1-10 dB of shadowingstandard deviation, respectively.

Combining the results of FIGS. 7 and 8, a graph of the maximum possiblesubscribers for given loading may be derived. Directing attention toFIG. 9, graphs of the maximum number of subscribers verses percentage ofthe cell area experiencing outage conditions for particular values ofthe shadowing standard deviation are shown. Specifically, lines 901-910present the maximum subscriber information for 1-10 dB of shadowingstandard deviation, respectively.

Reading FIG. 9, in a system where 2% outage and 9 dB of standarddeviation of the shadowing are experienced, it can be seen from line 909that the maximum number of active subscribers is 29. However, if byusing cell sculpting according to the present invention the standarddeviation of the shadowing is reduced to 4 dB, then it can be seen fromline 904 that the maximum number of subscribers may be increased toapproximately 38. Accordingly, further capacity gain associated withimplementation of the present invention in such a system of(38-29)/29=31% or 1.17 dB is achieved.

It should be appreciated from the above that traffic load balancing maybe a major source of capacity improvement. Subscribers' angulardistribution typically depends heavily upon morphology (buildings,malls, freeways, etcetera) which are often beyond the control of thenetwork designer. Morphology typically does not change very rapidly and,therefore, it is expected that a cell's loading at busy hours (whencommunication activity is at its peak) is relatively stable over time(although exceptions are possible, such as recreation areas betweensummer and winter).

To assess the long-term behavior of traffic load, two cellular marketswere analyzed; the San Jose, Calif. market and the Atlanta, Ga. market.For each market only three sector cells were considered. To assesstraffic change the statistical distribution of traffic as measured bycode usage was analyzed. Defining T_(α)[k,n], T_(β)[k,n], and T_(γ)[k,n]to indicate for the kth cell in the network the nth month busy houraverage levels of code usage for the alpha, beta, and gamma sectorsrespectively. The relative traffic loading is then defined for α, β, andγ sectors as:

If n=0 is defined as the reference month, the level of change may bedetermined by comparing the deviation from the reference as timeprogresses. For example, the change in the peak sector of the kth cellover a 6 month period is,

where the X in the R_(x)[k,n] denotes the busiest sector at time.

Directing attention to FIG. 10, a histogram of site loading changes inthe San Jose, Calif. market is shown wherein the x-axis represents thepercentage change in loading and the y-axis represents the probabilityof that change occurring. The loading changes of FIG. 10 are shown withrespect to 3, 5, and 11 months from the reference month n=0.

Directing attention to FIG. 11, the probability for change in trafficloads of at least 5, 10, and 15% are shown (lines 1101-1103respectively) versus month. From the above, it can be seen that, in mostcases, the traffic load ratio between sectors may generally be expectedto remain stable over a 12 month period. For example, the probability tohave a change larger than 10% over 6 months is approximately 8%, andover 12 months is approximately 16%. Accordingly, fixed systems may beimplemented such that cell sculpting of the present inventionsubstantially equalizes loading among cells and/or sectors. For example,loading information may be used with direction finding information todetermine cells and/or sectors which should be provided a particularcontour in order to result in substantially equal loading throughout thenetwork or some portion thereof.

From the above capacity gain analysis, it is expected that a fullyadjustable system implementing cell sculpting according to the presentinvention could provide on average approximately 35% capacity increaseto a typical prior art network configuration. However, as discussedpreviously, there are advantages to providing a passive personalitymodule, resulting in a fixed system. It is predicted from the analysisabove that such a fixed approach would result in approximately 10% lesscapacity increase as compared to a fully adjustable system, orapproximately a 25% capacity increase over a typical prior art networkconfiguration. Moreover, given the simplicity of the preferredembodiment personality module structure, it may be acceptable to replacethe cell sculpting modules periodically, such as every 12 months, tothereby provide capacity increases more near that achievable with afully adjustable system.

A preferred embodiment implementation of the present invention isillustrated schematically in FIGS. 12 and 13. Specifically, anarrangement of curvilinear arrays, here half dome arrays 1201-1203, areshown using simple passive beam forming networks of a preferredembodiment, here passive beam formers 1301 a-1303 b, to provide cellsculpting of the present invention with a desired level of diversityperformance in the links. The preferred embodiment curvilinear arraysare sections of a cylindrical antenna structure, such as shown in theabove referenced patent application entitled “Base Station ClusteredAdaptive Antenna Array” and U.S. Pat. No. 6,188,272 entitled “System andMethod for Per Beam Elevation Scanning,” spaced a suitable distanced dfrom a center point, such as approximately 200 cm, to provide decouplingthere between. For example, each curvilinear array may consist of anynumber of antenna elements or columns, preferably a relatively largenumber of antenna columns, which when coupled to the beam formersprovides desired antenna beam patterns. Preferably, equally spaceddipole antenna columns are utilized, such as columns 1211 a-1211 n, 1212a-1212 m, and 1213 a-1213 p of the illustrated embodiment, where n, m,and p are most preferably any number from 12 to 17 and the angle atthere between is preferably approximately 18°.

The use of such curvilinear arrays is advantageous when a desired beamwidth is relatively large, such as beam widths greater than 120 degrees.For example, the above described preferred embodiment half dome arraysare capable of forming very wide beams, such as on the order of 200° ormore, thereby leveraging the use of the preferred embodiment simplepassive beam forming networks.

In providing signal diversity, the illustrated embodiment groups theantenna array columns into groups (here a “right section” and a “leftsection”) for coupling to the beam formers. Referring to FIG. 13, it canbe seen that, in the illustrated embodiment, for transmission the rightand left sections are combined together to form transmit (TX) sectorbeams, while for receive, the right and left sections are fed directlyinto the receive (RX) diversity ports. This preferred embodimentprovides for both transmit sectorization flexibility and receivediversity.

Additionally or alternatively, dual polarization may be utilizedaccording to the present invention. For example, interleaved antennaelement columns of orthogonally polarized elements as shown in the abovereferenced U.S. Pat. No. 6,188,272 entitled “System and Method for PerBeam Elevation Scanning,” may be utilized where a first polarization(e.g., 45° polarization) provides a first section and a secondpolarization (e.g., −45° polarization) provides a second section of theabove example.

Although a preferred embodiment implementation of the present inventionhas been described with reference to the use of curvilinear arrays, itshould be appreciated that linear arrays, such as flat panel arrays, maybe utilized according to the present invention. Such flat panel arraysmay be utilized substantially as described above with respect to thecurvilinear arrays where more narrow beam widths are desired, such asbeam widths of 120° and less (although where wider beam widths aredesired a plurality of such flat panel arrays may be used with theappropriate feed circuitry to allow beam forming across multiplepanels). Moreover, such flat panel arrays having personality modules ofthe present invention may be used to directly replace existing BTSantennas to thereby provide advantages of the present invention withoutrequiring substantial alteration of the BTS.

Although the present invention and its advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the invention as defined by the appended claims. Moreover, thescope of the present application is not intended to be limited to theparticular embodiments of the process, machine, manufacture, compositionof matter, means, methods and steps described in the specification. Asone of ordinary skill in the art will readily appreciate from thedisclosure of the present invention, processes, machines, manufacture,compositions of matter, means, methods, or steps, presently existing orlater to be developed that perform substantially the same function orachieve substantially the same result as the corresponding embodimentsdescribed herein may be utilized according to the present invention.Accordingly, the appended claims are intended to include within theirscope such processes, machines, manufacture, compositions of matter,means, methods, or steps.

1. A method of providing improved cellular communications, said methodcomprising: determining a path loss angular profile for a cell, whereinsaid path loss angular profile provides azimuthal path loss informationwith respect to at least a portion of said cell; forming an antennapattern, using said path loss angular profile, such that path loss andantenna gain summed as a function of azimuth provide a substantiallyconsistent result; and implementing the antenna pattern using one ormore antenna elements.
 2. The method of claim 1, wherein saiddetermining said path loss angular profile includes use of footprintinformation with respect to said cell.
 3. The method of claim 1, whereinsaid determining said path loss angular profile includes use ofmonitored communication attributes in combination with direction findingfunctionality.
 4. The method of claim 1, wherein said substantiallyconsistent result provides a path loss differential wherein standarddeviation of shadowing with respect to a signal of interest andinterference energy is below 6 dB.
 5. The method of claim 4, whereinsaid standard deviation of shadowing with respect to a signal ofinterest and interference energy is approximately 4 dB.
 6. The method ofclaim 1, wherein said implementing the antenna pattern comprises:providing an antenna array having a relatively large number of antennaelements which have different signal weighting characteristics; andproviding a passive feed network coupled to said antenna array toprovide said different signal weighting characteristics.
 7. The methodof claim 6, wherein said relatively large number of antenna elements areprovided in a first group of antenna elements and a second group ofantenna elements, wherein said passive feed network provides signalpaths independently for said first and second group of antenna elementsfor substantially independent antenna pattern forming using said firstand second group of antenna elements.
 8. The method of claim 7, whereinsaid independent antenna pattern forming provides signal diversity in atleast one link direction of said cellular communications.
 9. The methodof claim 7, wherein said passive feed network also provides combining ofsignal paths for said first and second group of antenna elements forcombined antenna pattern forming said first and second group of antennaelements.
 10. The method of claim 9, wherein said independent antennapattern forming is used in a first link direction of said cellularcommunications and said combined antenna pattern forming is used in asecond link direction of said cellular communications.
 11. The method ofclaim 6, wherein said antenna elements having different signal weightingcharacteristics are associated with different antenna element columns ofsaid antenna array.
 12. The method of claim 6, wherein said antennaarray comprises a linear antenna array, and wherein said relativelylarge number of antenna elements is at least eight.
 13. The method ofclaim 6, wherein said antenna array comprises a curvilinear antennaarray, and wherein said relatively large number of antenna elements isat least twelve.
 14. The method of claim 1, wherein said path lossangular profile information is acquired at least in part from drive testinformation gathered with respect to said cell.
 15. The method of claim1, wherein said path loss angular profile information is acquired atleast in part from communication link attributes and associateddirection finding information.
 16. The method of claim 15, wherein saidcommunication link attributes include a receive signal strength.
 17. Themethod of claim 15, wherein said communication link attributes include acarrier to noise ratio.
 18. The method of claim 15, wherein saidcommunication link attributes include an energy per chip of a pilot to atotal received spectral density.
 19. A wireless communication systemcomprising: an antenna array having a relatively large number of antennaelements which have different signal weighting characteristicsassociated therewith; and a feed network coupled to said antenna arrayto provide said different signal weighting characteristics, wherein saiddifferent signal weighting characteristics provided by said feed networkare configured such that path loss and antenna gain summed as a functionof azimuth provide a substantially consistent result.
 20. The system ofclaim 19, wherein said antenna elements of said antenna array include afirst group of antenna columns and a second group of antenna columns,wherein said first and second groups of antenna elements are coupled tosaid feed network to provide signal diversity in at least one linkdirection.
 21. The system of claim 20, wherein a number of antennaelements of said first group of antenna elements is the same as a numberof antenna elements of said second group of antenna elements.
 22. Thesystem of claim 20, wherein said signal diversity is provided throughforming a first said at least one link direction beam using said firstgroup of antenna elements substantially independently of forming asecond said at least one link direction beam using said second group ofantenna elements.
 23. The system of claim 20, wherein said first andsecond groups of antenna elements are coupled to said feed network toprovide beam forming in a link direction other than said at least onelink direction using antenna elements of both said first and secondgroups of antenna elements.
 24. The system of claim 23, wherein said atleast one link direction is a reverse link and said link direction otherthan said at least one link direction is a forward link.
 25. The systemof claim 19, wherein said communication system comprises a basetransceiver station of a cellular network.
 26. The system of claim 25,wherein said base transceiver station provides communications using aCDMA protocol.
 27. The system of claim 25, wherein said base transceiverstation provides communications using a TDMA protocol.
 28. The system ofclaim 19, wherein said antenna array comprises: a linear phased array,wherein said relatively large number of antenna elements is at leasteight.
 29. The system of claim 28, wherein said linear phased array isone of a plurality of linear phased arrays of said wirelesscommunication system.
 30. The system of claim 29, wherein each linearphased array of said plurality of linear phased arrays includes at leasteight antenna elements which have different signal weightingcharacteristics associated therewith.
 31. The system of claim 29,wherein each linear phased array of said plurality of linear phasedarrays has a feed network coupled thereto, wherein each such feednetwork provides different signal weighting characteristics configuredsuch that path loss and antenna gain summed as a function of azimuthprovide a substantially consistent result.
 32. The system of claim 19,wherein said antenna array comprises: a curvilinear phased array,wherein said relatively large number of antenna elements is at leasteight.
 33. The system of claim 32, wherein said relatively large numberof antenna elements is at least twelve.
 34. The system of claim 32,wherein said curvilinear phased array is one of a plurality ofcurvilinear phased arrays of said wireless communication system.
 35. Thesystem of claim 34, wherein each curvilinear phased array of saidplurality of curvilinear phased arrays includes at least eight antennaelements which have different signal weighting characteristicsassociated therewith.
 36. The system of claim 34, wherein eachcurvilinear phased array of said plurality of curvilinear phased arrayshas a feed network coupled thereto, wherein each such feed networkprovides different signal weighting characteristics configured such thatpath loss and antenna gain summed as a function of azimuth provide asubstantially consistent result.
 37. The system of claim 19, whereinsaid feed network comprises: a passive feed network.
 38. The system ofclaim 37, wherein said passive feed network is comprised of a microstripline configured to provide impedances consistent with said differentsignal weighting characteristics.
 39. The system of claim 38, whereinsaid microstrip line comprises an air-line transmission line.
 40. Thesystem of claim 19, wherein said feed network comprises: a firstpersonality module adapted to be coupled to said antenna array andproviding a first configuration of signal weighting characteristics. 41.The system of claim 40, further comprising: a second personality moduleadapted to be coupled to said antenna array and providing a secondconfiguration of signal weighting characteristics.
 42. The system ofclaim 40, wherein said first personality module is decoupled from saidantenna array after a period of time in which topology and morphologyinformation with respect to a cell has changed and said secondpersonality module is coupled therefor.
 43. The system of claim 40,further comprising: a second antenna array having a relatively largenumber of antenna elements which have different signal weightingcharacteristics associated therewith, wherein said second personalitymodule is coupled to a second antenna array to provide said differentsignal weighting characteristics, wherein said different signalweighting characteristics provided by said second personality module areconfigured such that path loss and antenna gain summed as a function ofazimuth provide a substantially consistent result.
 44. A wirelesscommunication system comprising: an antenna system having a plurality ofcurvilinear arrays, wherein each curvilinear array of said plurality ofcurvilinear arrays includes a plurality of antenna element columns,wherein said antenna element columns of each said curvilinear array isdivided into at least two sub-arrays, wherein at least one of thesub-arrays comprises at least two of said antenna element columns; and afeed network coupled to said antenna system to provide signal weightingcharacteristics to signals associated with said antenna element columnsof said curvilinear arrays, wherein said feed network providessubstantially separate signal paths with respect to said sub-arrays ofsaid curvilinear arrays.
 45. The system of claim 44, wherein saidplurality of curvilinear arrays comprises three curvilinear arraysdisposed in a triangular relationship.
 46. The system of claim 44,wherein said sub-arrays and said substantially separate signal paths arecoupled to diversity ports of radio equipment to thereby providediversity signals with respect to said radio equipment.
 47. The systemof claim 46, wherein said feed network further provides signal pathswith respect to said sub-arrays of said curvilinear arrays which are notsubstantially separate to thereby provide for forming a beam usingantenna element columns of a plurality of sub-arrays of a curvilineararray.
 48. The system of claim 47, wherein said separate signal paths ofsaid feed network provide diversity coverage having a substantially samefootprint as a coverage area of corresponding not substantially separatesignal paths coupled to a same curvilinear array.
 49. The system ofclaim 47, wherein said substantially separate signal paths are utilizedin a reverse link and said not substantially separate signal paths areutilized in a forward link.
 50. The system of claim 44, wherein saidsub-arrays each include a same number of antenna element columns. 51.The system of claim 44, wherein each said curvilinear array of saidplurality of curvilinear arrays as coupled to said feed network providesa range of antenna beam synthesis from at least 10° to at least 170°.52. A wireless communication system comprising: an antenna system havinga plurality of curvilinear arrays, wherein each curvilinear array ofsaid plurality of curvilinear arrays includes a plurality of antennaelement columns, wherein said antenna element columns of each saidcurvilinear array is divided into at least two sub-arrays; and a feednetwork coupled to said antenna system to provide signal weightingcharacteristics to signals associated with said antenna element columnsof said curvilinear arrays, wherein said feed network providessubstantially separate signal paths with respect to said sub-arrays ofsaid curvilinear arrays, wherein said signal weighting characteristicsprovided by said feed network are configured such that path loss andantenna gain summed as a function of azimuth provide a substantiallyconsistent result.
 53. A system for providing wireless communicationswith reduced average transmit power, said system comprising: an antennaarray having at least eight antenna elements for which signal weightingis controlled independently; and a feed network coupled to said antennaarray and providing said independently controlled signal weighting,wherein said feed network is adapted to steer antenna beam transmitpower, using said signal weighting, in correspondence with directions ofhigh path loss, wherein said signal weighting is controlled such thatpath loss and antenna gain summed as a function of azimuth provide asubstantially consistent result.
 54. The system of claim 53, whereinsaid antenna array comprises a curvilinear antenna array.
 55. The systemof claim 54, wherein said at least eight antenna elements comprise atleast eight antenna columns.
 56. The system of claim 53, wherein saidantenna array comprises a plurality of curvilinear antenna arrays, eachof which having at least eight antenna elements for which signalweighting is controlled independently, wherein said curvilinear antennaarrays are disposed in a triangular arrangement to provide signalcommunication throughout a 360° service area.
 57. A wirelesscommunication system comprising: an antenna system having a plurality ofcurvilinear arrays, wherein each curvilinear array of said plurality ofcurvilinear arrays includes a plurality of antenna element columns,wherein said antenna element columns of each said curvilinear array isdivided into at least two sub-arrays; and a feed network coupled to saidantenna system to provide signal weighting characteristics to signalsassociated with said antenna element columns of said curvilinear arrays,wherein said feed network provides substantially separate signal pathswith respect to said sub-arrays of said curvilinear arrays; and whereinsaid signal weighting characteristics provided by said feed network areconfigured such that path loss and antenna gain summed as a function ofazimuth provide a substantially consistent result.
 58. The system ofclaim 57, wherein said plurality of curvilinear arrays comprises threecurvilinear arrays disposed in a triangular relationship.
 59. The systemof claim 57, wherein said sub-arrays and said substantially separatesignal paths are coupled to diversity ports of radio equipment tothereby provide diversity signals with respect to said radio equipment.60. The system of claim 59, wherein said feed network further providessignal paths with respect to said sub-arrays of said curvilinear arrayswhich are not substantially separate to thereby provide for forming abeam using antenna element columns of a plurality of sub-arrays of acurvilinear array.
 61. The system of claim 60, wherein said separatesignal paths of said feed network provide diversity coverage having asubstantially same footprint as a coverage area of corresponding notsubstantially separate signal paths coupled to a same curvilinear array.62. The system of claim 60, wherein said substantially separate signalpaths are utilized in a reverse link and said not substantially separatesignal paths are utilized in a forward link.
 63. The system of claim 57,wherein said sub-arrays each include a same number of antenna elementcolumns.
 64. The system of claim 57, wherein each said curvilinear arrayof said plurality of curvilinear arrays as coupled to said feed networkprovides a range of antenna beam synthesis from at least 10° to at least170°.